removing extra dependencies

Using jpeg for example, I saw I had a few packages that required it, but
as far as I see they do not it directly:
poppler-glib-0.10.4
gimp-2.6.6 (uses gegl for jpeg)
SDL_image-1.2.6
html2ps-1.0b4nb4
Do we have any scripts or tools to help track down bogus DEPENDS?